upgrade from N360 to Norton Security - details new

I've asked before and gotten some advice, but now becoming less clear.  Yank gave a response several weeks ago but now I'm no longer sure.  

I have the address to '...latestns ' to download JUST the installer for Norton Security, and I went to the store and BOUGHT a box with disc + Product Registration Key, and I plan to make the upgrade from Norton 360  to Norton Security Deluxe.  Can I simply run the Norton Security installer "over the top" of the already existing Norton 360?  Do I first need to use Control Panel of Window before running the N.S. installer?  Do I enter the product key code into the freshly installed product, or do I go to some online page like manage.norton.com and enter the product key there?  

Again, I am confused about all this.  I do not want to use the Norton Download Manager, but I want to make the upgrade to N.S.  What should be the detailed process?  Will I need Norton Removal Tool too?  I have not ever used the manage.norton.com site within the last two years, if ever.  There was a one time a Account.Norton.com or MyAccount.Norton.com or something which is no longer.